Chocobi Caramel

There are several radioactive that usually used for example Tritium, Carbon-14, Phosphorus-32, Sulfur-35, and Iodine 125-I

Ø Tritium (3H)

Maximum beta energy: 0.019 MeV, 100% emission.

Maximum range in air: About 1/6 of an inch

Radiological Half-life: 12.28 years.

Internal Occupational Limits:

Annual Limits on Intake-

Inhalation: 80 mCi

Ingestion: 80 mCi

Precautions for using Tritium:

1. Follow General Safety Precautions for all isotopes.


2. Traps may be necessary to collect tritium if large gas or vapor releases are anticipated. This will reduce the release to the environment.


3. Monitor surfaces routinely and keep record of the results. Geiger counters (survey meters) are not sensitive to tritium radiation and therefore wipe tests and a liquid scintillation counter are necessary to determine levels of contamination. Radiation badges are not issued to individuals using only tritium because the radiation emitted by tritium is not of sufficient strength to penetrate the badge.


4. Submit urine samples for analysis if requested to do so by the Radiation Safety Section. Yale's current Nuclear Regulatory Commission license requires an individual to submit a urine sample when working with 100 mCi or more of tritium at one time.


5. High activity tritium experiments may be performed in one of two laboratories (KBT 1138 and BCMM B-01) maintained by the Radiation Safety Section. Storage space is also available for high activity tritium stock solutions.


6. Due to the long half-life of tritium, tritiated waste must be segregated from short-lived waste. 3 H and 14 C waste maybe combined, but must be kept separate from 32 P,35 S,125 I and other radioactive waste.


7. Tritium can penetrate plastic and other materials. Stock vials should therefore be wipe tested routinely (ie, quarterly) to help prevent/control the escape of tritium from storage containers.

Notes and Special Precautions for Tritium

• H can NOT be detected with a portable survey meter. Surveys must be conducted using wipes and Liquid Scintillation Counting (LSC).


• Wipe tests required after each use.


• Liquid Scintillation Counter (LSC) efficiencies for 3H= 60 -70%.


• 3H spills are difficult to contain and time consuming to clean up. EHS Radiation Safety should be called immediately in the event of ANY 3H incident.


• 3H migrates - through containers (over time) and gloves.3H can contaminate inside of freezer, thus double containment is advised. Labs are encouraged to dispose of 3H when done using material. Even though 3H has a long half life, chemically it degrades and may not be useful.


• Urine bioassays required for some users; specifically required for those using > 100 mCi at a time, but also performed sometimes when 10 mCi is handled, tritiated water is used, or as follow up to 3H spills.

Ø Carbon-14 (14C)

Maximum beta energy: 0.156 MeV, 100% emission

Maximum range in air: about 8.6 inches

Radiological Half-life: 5730 years

Internal Occupational Limits:

Annual Limits on Intake-

Inhalation: 2 mCi

Ingestion: 2 mCi

Precautions for using Carbon-14

1. Follow General Safety Precautions for all isotopes.


2. Traps may be necessary to collect radioactive carbon dioxide if large gas or vapor releases are anticipated. This is to reduce the release to the environment


3. Monitor surfaces routinely and keep records of the results. Geiger counters are sensitive to the beta radiation from 14 Cif the probe is used within a 1/2 inch of the surface and the proper probe is used. Radiation Safety recommends a pancake type probe and a meter with a linear scale. With such a probe very low amounts of 14 C may be detected on a surface.


4. Average efficiency for 14 C with a pancake probe is approximately 3%. Do not cover the pancake probe with saran wrap® or parafilm®, etc. when using the probe to monitor for 14 C. This practice will decrease the efficiency of detection. Wipe tests should be taken and counted in a liquid scintillation counter for the most sensitivity when detecting removable surface contamination.


5. Radiation badges are not issued for individuals using 14 C as the badge is very unlikely to detect any radiation because of the short beta range in air.

Notes and Special Precautions for Carbon-14

• Liquid Scintillation Counter (LSC) efficiencies for 14C= 85-95 % - RECOMMENDED.


• Use a Pancake GM for personal post experimental surveys, but note; efficiency is poor (5-8%). Survey technique should be slow and close to the surface without touching.


• Keep in mind that even a few counts above background (bkg) means it is likely that counts are real.


• Very long half-life - 5730 Years. If clothing or shoes become contaminated, items will have to be taken for proper disposal. Please wear proper PPE.


• Expensive to purchase and to dispose of. Please order only necessary quantities.

Ø Phosphorus-32 ( 32 P)

Maximum beta energy:1.71 MeV, 100% emission.

Maximum range in air: 18 to 20 feet.

Radiological half-life: 14.29 days.

Internal Occupational Limits:

Annual Limits on Intake-

Inhalation: 0.9 mCi

Ingestion: 0.6 mCi

Precautions for using Phosphorus-32 ( 32 P)

1. Follow General Safety Precautions for all isotopes.


2. Perform dry runs and practice routine operations to improve dexterity and speed before using 32 P.


3. Avoid skin exposure by using tools to indirectly handle unshielded sources and potentially contaminated vessels.


4. Traps may be necessary to collect 32 P if large gas or vapor releases are anticipated. This is to reduce the release to the environment.


5. Monitor surfaces routinely and keep records of the results. Geiger counters with a pancake probe should be used for 32P radiation. Average efficiency for detecting 32 P with a pancake probe is 30%. Use wipe tests and a Liquid Scintillation Counter to determine levels of removable 32 P contamination.


6. Do not work over open containers of 32 P without shielding. Work with plexiglass shields (1/4 to 1/2 inch thickness). Shield all stock vials of 32 P. Do not use thin sheets of lead to shield 32 P.


7. Radiation badges are issued for individuals working with significant activities of 32 P. Individuals working with 10 mCi or greater will be issued an extremity dosimeter. Wear, store and return radiation badges as instructed by Radiation Safety.

Notes and Special Precautions for Phosphorus-32

• Skin dose main external hazard. Call EHS if skin is contaminated. High skin dosecan occur in a short period of time. For example - 1 μCi on skin for 8 hrs = over NRC ANNUAL skin dose limit of 50,000 mrem. Personal surveys are vital


• Use of safety glasses is important when working with 32P. Safety glasses serve as a radiation shield against the 32P betas as well as providing splash protection.


• Wear double gloves and change gloves often.


• Max Beta Energy = 1710 KeV: These high energy betas can penetrate into tissue – but only 0.8cm – so not a whole body dose. Only skin and eyes are at risk of an external exposure


• Ring badges issued for users of 10 mCi or more.


• Plexiglas shielding (3/8 in.) is very effective


• Short half-life -14.3 Days. If clothing items become contaminated, items may be returned after 12 half-lifes


• Shielding note: DO NOT use lead to shield 32P as high energy betas in lead can generate bremsstrahlung radiation (x-ray).

Ø Sulfur-35 ( 35 S)

Maximum beta energy: 0.167 MeV, 100% emission

Maximum range in air: about 9.6 inches

Radiological half-life: 87.4 days

Internal Occupational Limits:

Annual Limit on Intake-

Inhalation: 20 mCi

Ingestion: 8 mCi.

Precautions for using Sulfur-35 ( 35 S)

1. Follow General Safety Precautions for all isotopes.


2. Traps may be necessary if large gas or vapor releases are anticipated. This is to reduce the release to the environment. It may be necessary to incorporate activated charcoal into experiments involving volatile forms of 35 S.


3. Monitor surfaces routinely and keep record of the results. Geiger counters are sensitive to the beta radiation from 35 S if the probe is used within a 1/2 inch of the surface and the proper probe is used. The Radiation Safety Section recommends a pancake type probe and a meter with a linear scale. With such a probe very low amounts of 35 S may be detected on the surface. Average efficiency for 35 S with a pancake probe is approximately 8%. Do not cover the pancake probe with saran wrap® or parafilm®, etc. when using the probe to monitor for 35 S. This practice will decrease the efficiency of detection. Wipe tests should be taken and counted in a Liquid Scintillation Counter for the most sensitivity when detecting removable surface contamination.


4. Radiation badges are not issued for individuals using 35 S because it is very unlikely that any radiation exposure would be recorded because of the 35 S betas short range in air.


5. Proper tubes should be used for storage of single use aliquots of volatile 35 S material. Screw top tubes with rubber seals are recommended.

Notes and Special Precautions for Sulfur-35

• Use a Pancake GM for personal post experimental surveys, but note; efficiency is poor (5-8%). Survey technique should be slow and close to the surface without touching.


• Some chemical forms volatile... (Methionine/Cysteine, Translabel®, ProMix, Invitro cell labeling mix)

• Wear double gloves and changes gloves often.


• Large quantities (>10 mCi) stored at –80 can cause local contamination of freezer. Larger stock vials should be placed in a secondary storage container and activated charcoal should be incorporated into container.

Ø Iodine 125-I ( 125 I)

Maximum gamma radiation energy: 35 KeV

Maximum range in air: N/A

Radiological half-life: 60 days

Internal Occupational Limits:

Annual Limits on Intake:

Inhalation: .06 mCi

Ingestion: .04 mCi

Precautions for using Iodine 125-I ( 125 I)

1. Follow General Safety Precautions for all isotopes.


2. Use forceps fitted with rubber sleeves to ensure a secure grip on containers.


3. Radiation badges should be worn by all personnel involved in performing iodinations.


4. Radiation Safety approved hoods must always be used when performing iodinations.


5. Never remove the rubber vial septum on containers of volatile iodine! Remove all Na 125 I aliquots with Hamilton® hypodermic syringes inserted through the vial’s rubber septum. The stock vial containing Na 125 I should be purged with a charcoal trap before beginning the experiment. The Radiation Safety Section can supply you with charcoal traps.


6. If the iodination procedure requires a vacuum withdrawal of supernate or other substance containing iodine, an iodine trap should be placed between the collection flask and the vacuum source in order to protect the house vacuum line from contamination.


7. Store Na 125 I solutions at room temperature in a approved hood, do not freeze and avoiding heat Na 125 I solutions as this will result in subsequent volatilization.


8. Maintain a pH greater than 7 in Na 125 I solutions in order to reduce volatilization.


9. Have reducing agents available when using Na 125 I.


10. In the event of a spill involving volatile Na 125 I hold your breath and vacate the iodination area closing the doors behind you. Do not permit anyone to enter the spill area and contact the Radiation Safety Section immediately.


11. More information pertaining to thyroid counts may be obtained by calling 737-2139 or 785-4250. Thyroid counts are scheduled as required and performed in BCMM B-01.

Notes and Special Precautions for Iodine 125-I

· Personal surveys are vital.

· Use NaI probe for direct survey. NaI probes are very sensitive. Note: Bkg ~ 300cpm —GM Probes are NOT efficient ~ only at .07%.

· Wear double gloves and change gloves often.

· Toxic due to affinity for thyroid gland.

· Lead shielding and badges for mCi quantities.

· Careful of following issues which can increase volatility;

ü Do not freeze 125I,

ü Keep pH of iodine materials basic,

ü Do not use bleach to deactivate waste, use iodine based disinfectant instead.

(Source: Yale Environmental Health and Safety - http://www.yale.edu/ehs/Documents/rad/SpecificHandling)